JPS6024582B2 - Soldering equipment for flat pack parts - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a soldering device for input/output leads of components such as semiconductor integrated circuits, and more particularly to a soldering device for input/output leads of flat pack type components having a large number of terminals and a narrow lead pitch.

Conventionally, in order to reliably solder flat pack components such as semiconductor integrated circuits to a printed circuit board, the input/output leads of the component are first soldered, then mounted on the printed circuit board, and soldered. was.

Conventionally, when working with pick-up solder, the lead pitch is relatively large (2 to 3 skins), so good pick-up solder can be obtained by using large parts such as tweezers, dipping them in flux, and dipping them into a solder bath. It was possible. However, in recent years, the circuit mounting density of semiconductor integrated circuits and printed circuit boards has improved, and the lead pitch of components mounted on printed circuit boards has become extremely narrow (less than one rib). There was a solder bridge in between, which had to be fixed. SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an apparatus which prevents solder bridges from occurring in lead pick-up soldering work for flat pack type parts and which automatically performs flux application, soldering and cleaning work. In order to achieve this, the main feature of the present invention is to suction and hold the parts by vacuum suction, and immerse the suction and holding parts in the order of a flux bath, a solder bath, and a cleaning bath arranged circumferentially, and then to the solder bath. By setting the component approach/retreat angle, etc., it is possible to perform bridge-free pick-up soldering.

The present invention will be explained in detail below.

First, in order to obtain a soldered joint without bridges, we investigated the causes of bridge formation.

As a result, the following conclusions {a} to (g) were obtained. 'a- When soldering a flat pack type component using a solder bath, if the entire surface is immersed at once, solder tends to remain at the base of the leads and form bridges due to surface tension.

For this reason, dipping into the solder bath is performed one side at a time with a slope. 'b} As a result of examining the entrance and retreat angles of the leads into the solder bath, as shown in FIG. 4, as the angle increases from 0 to 450, the bridge occurrence rate decreases. 45o
It becomes almost 0 at ~750, and increases again at 750 or more.

For this reason, the angle of entry and retreat is preferably 450 to 750. 'c} As a result of examining the speed of entering and retracting the solder bath, as shown in FIG. 5, the incidence of bridging decreases as the speed increases.

In particular, the incidence of bridging can be minimized at 5 arc/sec or more for approach and 10 arc/sec or more for retreat. However, if the speed is increased, it is considered that waves will be generated and falls due to impact, so an approach speed of 5 to 10 m/sec and a retreat of 10 to 20 m/sec is appropriate. 'd) As a result of examining the immersion time in the solder bath, as shown in Figure 6, the shorter the immersion time, the lower the incidence of bridging.

In particular, it is extremely low at 0.9 seconds or less. {e}
As a result of examining the immersion depth of the lead of the component, as shown in Figure 7, if the lead is immersed below the molded part (position 2), the bridge will be thinner than if it is immersed above the molded part 2. Incidence is low.

'f} If an oxide film remains on the surface of the solder bath during soldering, this will cause a bridge.

Therefore, it is necessary to remove the oxide film immediately before dipping.
3) Immediately before soldering, it is necessary to apply flux to the leads to improve their solderability.

Further, after soldering, cleaning is required to remove the remaining flux. In order to fully satisfy these requirements, we have provided the device with the following features.

(2) As shown in Figures 1 and 2, so that flux application, solder bonding, and cleaning can be performed continuously, the sieves are arranged in a circumferential manner, and the elements can be attracted and transported.

In addition, each tank was shaped so that the handling part 7 could be moved up and down automatically by fluid pressure using a cylinder 25 or the like.

■ Enter and retract angle of lead into solder bath from 45o to 7
50, the handling part 7 was given a certain inclination so that the approach and retreat angles could be set in a state where the parts were sucked.

■ Immediately before immersing the parts into the solder bath, wipe the wiper (8th
Figure 10') was moved back and forth on the surface of the solder bath to remove the oxide film.

■ The speed of approach and retreat into the solder bath can be adjusted to 5 to 10 c/sec for approach and 10 to 20 c/sec for retreat by installing flow rate adjustment valves 27 and 28 on the cylinder 25 that moves the hand link up and down. I made it.

(2) The solder soaking time can be set to 0.9 steps or less by providing a timer or the like to hold the fluid flowing into the cylinder 25 for a certain period of time. ■ The depth of soldering into the solder bath is determined by making the stroke of cylinder 25 shorter than the maximum stroke.
It can be adjusted so that it is below the lead forming part.

■ In order to immerse the lead of the component one side at a time, after immersing the groove on one side, rotate the head by 360o/n (plane) using the head rotation gear or roller (Fig. 10, 19, 20), and repeat this operation n times. This was done so that the entire surface was immersed. ■ Vacuum suction is used in the handling section to grasp parts, but
As shown in FIG. 12, a ring 21 made of a rubber material is used at the tip of the handling portion of the component suction surface to prevent the device from being immersed due to air leakage and from falling during transportation.

An embodiment of the present invention will be described in detail below. FIG. 1 is its plan view, and FIG. 2 is its AA sectional view. This embodiment consists of a component supply section a that performs set suction of components, a flux application section b that immerses component leads in flux liquid, a solder immersion section c that immerses component leads in molten solder liquid, and a rough cleaning liquid that immerses component leads in molten solder liquid. A rough cleaning section d for immersing component leads in a finishing cleaning solution, a finishing cleaning section e for immersing component leads in a finishing cleaning solution, a component extraction section f for taking out the parts that have been processed in a to e as external products, and each of these parts. and a transport section g having a turntable 8 for sequentially transporting parts.

The parts a to f are arranged in the order described above at regular intervals (every 60 degrees) below the periphery of the turntable 8 of the transport section g, and the parts are sucked and transported to the outer peripheral position of the turntable 8 corresponding to the arrangement. Handling parts 7a to 7f are attached. The turntable 8 is rotatably supported by a base 33 via a shaft 32, and the shaft 32 is controlled by a control mechanism (not shown) provided in the base 33 to complete each of the steps a to f above. It is controlled so that it rotates 60 degrees each time. This control mechanism is outside the scope of the present invention and will not be specifically described. The ball 32 has a built-in pipe 31 for transmitting vacuum pressure, and the vacuum pressure supplied from another vacuum pressure generation source (not shown) is passed through six rubber pipes 31a to 31a.
31f, and applied to handling parts 7a to 7f provided at six locations on the circumference of the turntable 8 for picking up parts. As shown in FIG. 10, the handling unit 7 (7a to 7f in FIG. 2 are collectively referred to as 7) is connected to an arm 36 extending in the vertical direction of the turntable 8, and is connected to an arm 36 that is connected to an arm 36 that is connected to a vertical drive shaft 16. It is mounted so that it can be moved. The vertical drive shaft 16
is normally located directly above by a spring 37, and is pushed down by a separately provided head pusher 9. A hand link main body 18 is attached to the lower side of the shaft 16, and a subline shaft 22 shown in FIG. 11 is housed in the main body 18 so as to be rotated 90 degrees at a time using a ball lock system. There is. Inward direction of the spline shaft 22 (shaft 3
An opening for taking in vacuum pressure from a pipe 31 and a head rotation gear (or roller) 19 are integrally provided at the end (in both directions), and a pipe-shaped component suction head 17 is provided at the outer end. There is. A rubber ring 21 as shown in FIG. 12 is attached to the suction port of the head 17 that suctions parts.
Eliminates air leaks from component surfaces and improves suction efficiency. The arm 36 to which the handling part 7 is attached is designed such that the approach and retreat angles Q (shown in FIG. 9) are set between 45o and 750o when the lead of the component 15 enters and retreats into the solder bath. , is bent downward from the turntable 8 and has a predetermined inclination. The component suction head 17 is rotated 90 degrees at a time to immerse the base 3.
Drive gear warming shafts 38 are provided at positions corresponding to b to e of 3. For example, when the handling portion 7 is raised to the position shown in FIG. 10, the balls 38 are rotated in the approaching direction.
The drive gear 20 attached to the arm 37 is engaged with the head rotation gear 19, and the gear 19 is rotated by 90 degrees.

When the 90 degree rotation is completed, the shaft 38 is rotated in the separating direction,
The gear 20 provided on the arm 37 is separated from the gear 19.

Thereafter, the head pusher 9 is pushed down and the reed shielding surface of the component 15 is wetted again. As shown in FIG. 1, the head pusher 9 that lowers the handling section 7 has a flux application section b, a solder bonding section c, and a rough cleaning section d.
, finish cleaning section e, and are provided near four locations, respectively, so as to push down the vertical drive shaft of the handling section 7 when it comes to the corresponding position.

The structure of the head pusher 9 is, as shown in the right head pusher 9e (head pusher near the finishing cleaning tank) in FIG. The head pusher 9e is composed of a head pusher 9e, and a cylinder 25e that causes the head pusher 9e to move in an arc around the fulcrum. The operation of the cylinder 25e is performed by the action of air pressure or oil pressure controlled and supplied by a control mechanism (not shown) provided under the base 33, but this point is also outside the scope of the present invention. The explanation will be omitted. The details of the component supply section a are shown in FIG. 13, and in order to set the component 15 in a constant position and in a constant direction, a square groove 36 that matches the shape of the component is formed on its surface, and one end is connected to a horizontal shaft 34. and a cylinder 26a that pushes up the parts supply table 1 as shown by the dotted line.
The component 15' pushed upward comes into contact with the suction port of the component suction head 17 of the preparation handling section 7, and is suctioned by the vacuum pressure from the rubber pipe 31a.

After the component suction, the piston 35 of the cylinder 26a is lowered to its original position, and the component supply table 1 returns to its original horizontal state. The operation of the cylinder 26a is performed by air pressure, oil pressure, or the like that is controlled and supplied by a control mechanism (not shown) provided under the base 33. Since this point is also outside the scope of the present invention, the explanation will be omitted. FIG. 13 also shows the structure of the component take-out section f, whose operation is almost the opposite of that of the component supply section V.

When the code shown in parentheses is the parts ejecting part f, it is specially attached. 6 indicates the parts ejecting table, 26f indicates the parts ejecting cylinder, and the code without parentheses indicates the parts supply part. The sign is the same as in case a. That is, the handling section 7
The component 15' that has been sucked and conveyed by the component suction head 17 is received by the square groove 36 of the component pick-up table 6 at the dotted line position, and when the vacuum pressure of the suction head 17 is removed, the component pick-up table 6 , the piston 35 of the parts removal shilling 26f is lowered and returns to the horizontal position shown by the solid line, and the part 15 can be removed. As shown in FIGS. 1 and 2, the flux application section b includes a flux tank 2 containing a flux liquid 39 installed on a base 33 below the handling section 7b.
, a head pusher mounting column 30b installed on a base 33 in the vicinity thereof, a head pusher 9b engaged with the upper end of the column 30b as a fulcrum, and a cylinder 25b that performs a depressing operation of the head pusher.

The surface height of the flux liquid 39 is maintained at such a level that when the handling portion 7b is lowered by pressing down the head pusher 9b, the soldered portion of the lead of the component being sucked and held is immersed therein. Specifically, the cylinder may be provided with a screw stopper that can adjust the stroke of the cylinder 25b. In order to keep the height of the liquid 39 constant, for example, the bottle containing the liquid may be turned upside down and its opening adjusted to the desired liquid level height. This technique of keeping the liquid level constant can also be used in the cleaning tanks 4 and 5. The solder immersion part c is the first
As shown in the figure, a solder bath 3 containing a solder melt,
The other components are the same as the flux application part, including a head pusher 9c, a head pusher mounting column 30c, and a cylinder 25.
It consists of c.

In addition, there is a valve 27 that adjusts the amount of oil (noble air) flowing into the cylinder, and a valve 28 that adjusts the amount of oil (noble air) flowing into the cylinder, in order to set the entry and retreat speeds when dipping the component lead into the molten solder. This valve is adjusted in advance so that the approach speed is 5 to 10 per second and the retraction speed is 10 to 20 per second. As shown in FIG. 8, the solder bath 3 contains molten solder 16, and a wiper 10' is used to remove the solder oxide film formed on the surface of the solder surface 16 before soldering. It is designed to scratch in one direction. The operation of this wiper 10' consists of a cylinder 11 that causes the wiper frame 10 to reciprocate in the horizontal direction;
This is accomplished by a cylinder 2 which is attached to the wiper frame 10 and which moves the wiper 10' in the vertical direction to remove it from the solder liquid surface and immerse it in the solder liquid. The driving of these cylinders is also controlled by a control mechanism (not shown) provided on the base 33.
The explanation is omitted. As for the depth of solder bonding, as shown in FIG.
Provided for. The coarse cleaning tank d and the finishing cleaning tank e have the same structure as that of the flux application section, except that the liquid contained in the tank is a cleaning liquid (for example, alcohol, Freon, etc.), so a description thereof will be omitted.

Next, the operation of the apparatus of this embodiment will be explained.

FIG. 14 is a flowchart showing the overall main operations along the flow of parts, and FIGS. 15 to 18 are flowcharts showing detailed operations of each part in FIG. 14. A description will be given below according to these flowcharts. 'a} For setting and suction a of the parts, perform the operations from ■ to 1 in FIG. 15.

First, the component 15 is supplied from the outside through the square groove 36 (the first
(Fig. 3). When this device starts operating, the first
The supply table 1 of the component supply section a shown in FIGS. In close contact. This cylinder 26a
When the movement of the suction valve 40 is detected (for example, by detecting a magnetic change seen from the cylinder surface due to the movement of the piston), the suction opening/closing lever 41a is lowered to open the suction valve 40. Then, vacuum pressure is applied to the suction head 17a, and the part 15
' is attracted to the suction port of the suction head 17a. In addition, if the component 15 is not set on the supply table, the suction port of the suction head 17a will be in an open state, and the inflow of air above a certain level will interfere with the vacuum pressure supply to other handling parts. If so, the adsorption valve 40 is closed by, for example, a ball valve to prevent air from flowing in beyond a certain level. When the component suction is completed, the supply table 1 returns to the position indicated by the solid line in FIG. 13 (horizontal state) by the lowering of the piston of the cylinder 35. The turntable 8 rotates 60 degrees, and the handling section 7a that has been attracted to the component 15 is transported to the position of the flux application section b. The handling part that has come to this position b is indicated by the symbol b attached to each part, for example, handling part 7b, and the handling part that has arrived at position c
Here, c is added and the same applies to the following positions d to f. 'b) The pusher 9b provided in the flux application section b is pushed down by oil pressure (or air) supplied to the cylinder 25b, and the vertical drive shaft 16 of the handling section 7a is pushed down by the pusher 9b and lowered.

As a result, the component 15 adsorbed by the head portion 17a of the handling portion 7a is immersed in the flux tank 2. The direction of this immersion operation is indicated by the arrow in FIG. 9, and the immersion depth is up to the molded portion D of the lead 41. Approach and retreat angle Q during infiltration
is determined by the arm 36 (Fig. 10) to which the handling part 18 is attached, and by the way, as shown in Fig. 9, 4
It is set between 50 and 750. In the case of flux, the soaking time is preferably held for several seconds, and this time is controlled by the holding time after oil pressure (or air) is supplied to the cylinder 25b. After this, in order to raise the pusher 9b, the hydraulic pressure (or air) to the cylinder 25b is made to flow in the opposite direction.
The pith 16 is raised by the spring 37b of the shaft 16b, and the part 1 that is attracted to the head 17b of the handling section 7b is
5 separates from the flux in flux tank 2 and rises.
Next, the shaft 38b rotates and the drive gear 2 of the arm 37b
0b is brought closer to the gear 19b, and when they mesh with each other, the head rotation gear 19 rotates 900 times by the drive gear 20.
The ball 24 shown in FIG. 11 falls into the recess of the spline ring 22 and is locked. The above is the operation of the flow @~■ in Fig. 16, and until the four shielding surfaces of the leads 41 of the component 15 are completed, that is, by changing the lead surfaces by 90 degrees, the flow @ in Fig. 16 is completed.
~■ Return 4 lines. Next, the turntable 8 rotates 60 degrees, and the handling section 7b that has picked up the component 15 moves to position C. c) At the same time as this transportation, the oxide film on the solder bath 3 is removed to improve solder adhesion.

This oxide film removal operation is carried out by raising the wiper 10' using the cylinder 12 attached to the wiper frame 10 shown in FIG.
In the cylinder 11, the wiper frame 10 together with the cylinder 12
Draw it to the left side of the diagram. Next, the wiper 1 is
0' and push the wiper frame 10 together with the cylinder 12 to the right in the figure using the cylinder 11. Due to the pushing action of the cylinder 11, the wiper 10' scratches the surface of the molten solder to remove oxidized pus formed by heating and oxidation. Next, it is transported to the solder soaking part c position, and the operations shown in FIGS.

The solder dipping operation differs from the flash coating operation in that various operating conditions are precisely set. That is,
■The approach and retreat angles to the molten solder surface are 45 to 75 degrees, ■The approach speed is 5 to 10 mm/S, and the retreat speed is 10 to 75 degrees.
The ratio of 2 is 1, and the time to soak in the molten solder is 0.9.
-■ The depth of the lead soaked into the molten solder is up to the position of the lead forming part (bending part).
The occurrence of bridges between leads can be minimized. As mentioned above, the approach and retreat angle of
It is determined by the angle at which the handling part is attached to the head pusher 9, that is, the downward bending angle of the arm 36.
It is designed to move in and out at an angle of 45 degrees to 75 degrees simply by pressing the button c. ■The approach speed and retreat speed are also
As mentioned above, the hydraulic (air) inflow amount adjustment valve 27 to the shilling 25c and the valve 28 that adjusts the outflow amount,
The hydraulic pressure (air) at a constant pressure is applied to the cylinder 25.
By simply letting it flow in and out of
Enemies, Retreat: 10-2 Enemies/S) can be obtained. The time for soaking into the molten solder (2) is similar to the control of the soaking time to the flux tank, by shortening the switching time from the hydraulic (air) inflow to the cylinder 25c to the outflow, and reducing the droplet soaking time to 0. It is controlled by a control mechanism under the base so that the time is 5 seconds or less. The depth of the lead immersed in the molten solder in (2) is also up to the lead forming part, as in the case of the flux bath, and this adjustment is made by a threaded collar that can adjust the stroke of the cylinder 25c, and is set in advance. . When the solder bonding operation is completed, the turntable 8 is further rotated by 60 degrees, and the handling section 7c that has picked up the component 15 is moved to the position d where the next rough cleaning is to be performed.

[d} Rough cleaning d performs the operations of ■ to ■ in Fig. 7, and when the pusher 9d is pressed down, the handling part 7d
16d is pressed down, and the head 17d, on which the component 15 is sucked, is moved downward by the lowering of the handling part.
Lead 4 of the component 15 going down toward the rough cleaning tank 4
1 descends until it is immersed in the rough cleaning liquid, the descent stops, and the shaft 38
d is rotated, and the drive gear 20d is closely engaged with the head rotation gear 19d.

In this meshed state, the drive gear 20d slowly rotates the head rotation gear 19d by 270 degrees (by four reed faces). As the head 17d rotates, the component 15 that is attracted to the head 17d is rotated, and all the leads that are shielded on four sides are cleaned. When this cleaning work is completed, the pusher 7d is raised to its original position, and the handling part 7d on which the parts are sucked rises, making it possible to transport the parts. Furthermore, the turntable 8 rotates 60 degrees and moves to the position e where final cleaning is performed.

[c--Final cleaning e performs exactly the same operation as rough cleaning, so a detailed explanation will be omitted.

When the final cleaning is completed, the turntable 8 is further rotated by 60 degrees and moved to the position f where parts are taken out.

The component take-out operation f consists of the operations ■ to @ shown in FIG. 18, and is almost the opposite of the component setting suction operation a.

That is, in FIG. 13, the Toji mounting base 6 is pushed up by the cylinder 26f, and the component 1 sucked by the component suction head 17f is removed.
5' is received by the dotted line. In this state, the lever 41f shown in FIG. 10 is pressed against the adsorption valve 40f to close the vacuum pressure supply path of the pipe 31. As a result, the component 15' no longer receives the suction force from the suction head, and the mounting base 1 shown in FIG.
is lowered to the solid line position by cylinder 26f. In this state, the parts that have been completely processed can be taken out from the take-out stand 1. Further, the turntable 8 is rotated 60 degrees, and the handling section 7f' where no components are being picked up is moved to the position a where the next set of components is to be picked up.

During this movement, the lever 41f continues to close the suction valve 40f, and remains closed until the parts are set and the suction operation is performed. With the above structure, according to the present invention, it is possible to solder flat pack components with narrow lead spacing.
This method can be performed automatically without causing bridging, and has a great effect on improving the reliability of lead soldering for high-density devices, which has recently been the case.

[Brief explanation of the drawing]

Fig. 1 is a plan view of a pick-up soldering device that is an embodiment of the present invention, Fig. 2 is a cross-sectional view taken along the line AA, Fig. 3 is a perspective view of a flat-back type component, and Figs. 4 to 7 show bridge formation. 8 is an enlarged perspective view of the solder bath shown in FIG. 1, and FIG. 9 is a diagram showing the state of components immersed in the solder bath.
Figure 10 is a diagram showing the handling section and its surroundings in Figure 1, Figures 11 and 12 are partial cross-sectional views of Figure 10, and Figure 13 is a diagram showing the handling section and its surroundings.
The figure is a perspective view showing the component supply section a and the component removal section f in FIG. 1, and FIGS. 14 to 18 are flowcharts showing the operation of this embodiment. a...Component supply section, b...Flux application section, c...Solder soaking section, d...
Rough cleaning section ~ e... Finish cleaning section, f...
・・Component extraction section, D ・・Lead forming section, G・・
...Transportation section, 1...Parts supply table, 2...
...Flux bath, 3...Solder bath, 4...
Rough cleaning tank, 5...Finish cleaning tank, 6...
・Parts removal stand, 7... Handling unit, 8... Turntable, 9... Head pusher, 10... Wiper frame, 1
0'...Wiper, 1 1, 12...Shilling, 15...
Flat pack parts, 14...Solder liquid level, 1
6... Vertical drive shaft, 17... Component suction head, 21...'' ring, 22... Spline shaft, 2
4... Ball, 25, 26... Cylinder, 27, 2
8... Valve, 41... Lead. Kan' Zuken 2 Zu Kai 34 Figures 4 Figures Many Figures Many Figures 7 Figures Kiln'' Figure 8 Figure Nest? Drawing brother 'o figure false Z figure folding box trying figure many '3 figure many' figure number 7 figure figure 18 figure

Claims (1)

[Scope of Claims] 1. A component holding means for sucking and holding a component, a circumferential transfer means for transferring the component holding means circumferentially, and a flux tank disposed below the circumference according to the procedure of pick-up soldering process. , solder tank,
and a cleaning tank, and when the parts holding means provided corresponding to each tank reaches the top of each tank, the parts held by the holding means are lowered into the tank, and after predetermined processing is performed, the parts are raised again. 1. A device for picking up and soldering flat pack type parts, characterized in that it is equipped with means for lowering and raising parts. 2. A component suction head to which vacuum suction pressure is supplied is attached to one side of the component holding means, and a vertical drive shaft supported by the transfer means so as to be movable in the vertical direction is attached to the upper part; 2. The apparatus for soldering flat pack type components according to claim 1, wherein a head pusher for pushing the vertical drive shaft downward is attached to the component lowering means provided for each tank. 3. The device for soldering flat pack type components according to claim 2, wherein a rubber ring is attached to the component suction surface of the component suction head to prevent leakage of vacuum suction pressure. 4. Claim 1, wherein the component holding means is provided with a ball locking means that rotates and locks the ball every time it rotates by 360°/n in order to perform a dipping operation on the n-plane of the component terminal surface.
An apparatus for soldering flat pack type parts as described in 2. 5. A soldering device for flat pack type parts as claimed in claim 1, which enters and retreats at an angle of 45 degrees to 75 degrees with respect to the liquid surface when immersed in a solder bath. 6 When dipping into the solder bath, approach speed: 5 to 10 cm/
S, Immersion time: 0.5 seconds or less, Retraction speed: 10-20c
2. The apparatus for soldering flat pack type parts according to claim 1, wherein the soldering device is m/S. 7. The apparatus for soldering flat pack type parts according to claim 1, wherein the immersion depth is equal to or less than the molded part of the lead when immersed in the solder bath.